The present disclosure relates to bearing assemblies having labyrinth seals and more particularly to a bearing assembly having a labyrinth seal that purges contamination.
Conventional bearing assemblies include a housing, a bearing mounted in the housing, and a shaft mounted in the bearing for rotation relative to the housing. Seals are provided between the housing and shaft to prevent contaminants outside the housing from entering the housing and damaging the bearing. As will be appreciated by those skilled in the art, relative motion occurs between the seal and either the shaft or the housing, which causes wear. In order to reduce seal wear, the seal is pressed onto either the housing or the shaft and a small gap is provided between the other element. For example, if the seal is pressed into a seat formed in the housing, a small clearance gap is provided between the seal and the shaft so the seal and the shaft do not contact as the shaft turns in the seal. This reduces seal wear and increases the life of the bearing assembly.
Lubricant is introduced into the housing of the bearing assembly to reduce wear and friction between the moving parts. During operation, the lubricant in the housing is pressurized to prevent contaminants from entering the housing through the clearance gap where the contaminants could damage the bearing and reduce bearing assembly life. However, under some conditions, the lubricant pressure can drop, permitting contaminants to enter the housing through the clearance gap, damaging the bearing and significantly reducing the life of the bearing assembly. Thus, there is a need for a non-contact seal (i.e., a seal providing a clearance gap) that purges contaminants from the clearance gap regardless of lubricant pressure in the housing.